Locking means for swivel chair



Oct. 14, 1958 G. w. LUHRS LOCKING MEANS FOR SWIVEL CHAIR Filed March '7, 1957 I INVENTOR.

GlLBERT LUHRS Patented Get. 14, 1958 LOCKING MEANS FOR SWIVEL CHAIR Gilbert W. Luhrs, Kankakee, lll., assiguor to Sears, Roebuck and Co., Chicago, 111., a corporation of New York Application March 7, 1957, Serial No. 644,639 2 Claims. (c1. 155--95) This invention relates generally to improvements in swivel chair constructions and more particularly to locking means for locking the seat of a swivel chair in a desired position of use.

One of the objects of this invention is the provision of a simple and efficient means for locking the seat of a swivel chair in a desired position relative to the base of the chair.

Another object of my invention is the provision of a locking means of the foregoing character which is easily accessible to and readily manipulable by the chair user.

Other and further objects and advantages of my invention will become apparent from the following description when considered in connection with the accompanying drawings in which:

Fig. 1 is a fragmentary perspective view looking upwardly to the underside of a swivel chair embodying my invention.

Fig. 2 is a fragmentary side elevational view on an enlarged scale and showing the locking means in a retracted position.

Fig. 3 is a front elevational view of the structure illus trated in Fig. 2.

Fig. 4 is a cross-sectional view taken substantially on line 44 of Fig. 3 and Fig. 5 is an elevational view of a structural detail.

Referring to the drawings the numeral designates generally a base structure formed of intersecting tubular members including horizontal portions 11 forming a seat support and integral leg portions 12. A conventional swivel fixture 13 is bolted to the horizontal portions 11 and is secured by screws to the underside of a seat member 14. The foregoing is of generally conventional construction and forms no part of the present invention.

My invention comprises a generally U-shaped bracket 16 formed of sheet metal the upper leg 17 of which is secured to the underside of the seat member 14 as with screws. The lower leg 18 of the bracket is disposed slightly above the horizontal tubular portions 11 so as to provide clearance between the bracket and said portions. The upper and lower legs are connected by a vertical leg 19. The upper and the lower legs 17 and 18 of the bracket are provided each with an aperture, the said apertures being in vertical alinement and adapted to slideably receive a bolt member 21, as will be seen clearly in Fig. 4. The seat member 14 is provided with a recess 22 in registration with the apertures of the legs 17 and 18 to accommodate the upper end of the bolt member 21 when the same is in retracted position. A latterly directed arm 23 is fixed in the bolt member 21, the end of the arm being provided with a knob portion 24. As can be seen clearly by reference to Fig. 3, the arm 23 extends through a slot 25 in the vertical leg 19. Said slot is angularly inclined with the extreme upper portion constituting an extension and being oppositely inclined as illustrated clearly in Fig. 5. The slot 25 affords a camming action on the arm 23 as the same as moved along the slot to effect axial movement of the bolt member 21. Thus, by the movement of the arm 23 the bolt member 21 may be moved to retracted or extended positions, as will be hereinafter explained.

A coil spring 26 concentric with the bolt member 21 and having its opposite ends abutting against the upper leg 17 of the bracket and the lateral arm 23 tends to bias the bolt member 21 in a downwardly direction and thus serves to maintain the said bolt member either in retracted position, when the arm is in the upper angular extension of the slot, as illustrated in Fig. 3 or in extened or operative position when the arm is at the lower end of the slot.

Each of the horizontal portions 11 is provided with an aperture 27 which is so arranged as to be in registration with the bolt member 21 when the same is brought into alinement, as when the seat member 14 is rotated. When it is desired to deactivate the locking means, the arm 23 is moved to the position illustrated in the Figs. 3 and 5 wherein the lower end of the bolt member 21 is substantially flush with the underside of the lower leg 18 of the bracket. In order to render the locking means of my invention effective for use, the arm 23 is moved to the lowermost position in the slot as illustrated by the broken lines in the Fig. 4 in which position the lower end of the bolt member extends below the lower leg 18. As the seat member 14 is swivelled relative to the base 10 the bolt member 21 which has a rounded lower end is caused to be cammed upwardly by the circular contour of the tubular portions 11. When the bolt member 21 is moved into registration with an aperture 27 the spring 26 urges the bolt member to seat in the aperture and thereby to lock the seat member 14 in a desired position of adjustment. In order to change to another position it is merely necessary to move the arm 23 upwardly in the slot 26 to effect disengagement of the lower end of the bolt member 21 from the recess 22 and then to rotate the seat member.

Various changes and modifications coming within the scope of my invention will doubless suggest themselves to those skilled in the art. Hence I do not wish to be limited to the specific forms shown or uses mentioned.

I claim:

1. In combination, a base, a seat member swivably mounted on said base, a bracket having vertically spaced horizontal leg portions and a connecting vertical leg portion, the said bracket being connected by the upper of said leg portions to said seat member in depending relation thereto, a bolt member slidably supported in said horizontal leg portions, the vertical leg portion having an inclined slot, an arm extending laterally from said bolt member and passing through said inclined slot, said slot affording camming means for axially moving said bolt member, said base having means to engage with the end of said bolt member to lock said seat member relative to said base.

2. The invention as defined in claim 1 including means for normally biasing said bolt member to extended position.

References Cited in the file of this patent UNITED STATES PATENTS 1,639,371 Freeman Aug. 16, 1927 2,306,891 McArthur Dec. 29, 1942 2,334,193 Hedeen et al Nov. 16, 1943 FOREIGN PATENTS 1,905 Great Britain 1908 

